The largest county in Colorado
There are two right answers. By land area it is Las Animas County; by population it is El Paso County. Which one you want depends on what you meant by largest.
Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.
By land area
| Rank | Name | Land area | Population |
|---|---|---|---|
| 1 | Las Animas County | 4,773 sq mi | 14,391 |
| 2 | Moffat County | 4,743 sq mi | 13,122 |
| 3 | Weld County | 3,985 sq mi | 378,426 |
| 4 | Mesa County | 3,329 sq mi | 162,845 |
| 5 | Gunnison County | 3,239 sq mi | 17,439 |
| 6 | Rio Blanco County | 3,221 sq mi | 6,683 |
| 7 | Saguache County | 3,169 sq mi | 6,732 |
| 8 | Garfield County | 2,947 sq mi | 63,474 |
| 9 | Larimer County | 2,596 sq mi | 377,292 |
| 10 | Lincoln County | 2,578 sq mi | 5,645 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | El Paso County | 757,040 | 356 per sq mi |
| 2 | Denver County | 740,613 | 4,838 per sq mi |
| 3 | Arapahoe County | 673,820 | 845 per sq mi |
| 4 | Jefferson County | 580,451 | 759 per sq mi |
| 5 | Adams County | 554,668 | 475 per sq mi |
| 6 | Douglas County | 399,396 | 475 per sq mi |
| 7 | Weld County | 378,426 | 95.0 per sq mi |
| 8 | Larimer County | 377,292 | 145 per sq mi |
| 9 | Boulder County | 328,560 | 452 per sq mi |
| 10 | Pueblo County | 169,277 | 70.9 per sq mi |
And the smallest
More on Colorado
Rebuilt from source data 30 August 2026. How these figures are produced.